The present invention relates to an apparatus for metering, sifting and feeding a powder, such as for the application of powdered seasoning to the outside surface of a processed food product.
Apparatus commonly used for the application of powdered seasoning to processed food dispenses the powder over the path of a conveyor transporting the food. One such apparatus is described in U.S. Pat. No. 3,152,010 issued to W. W. Case. The Case patent discloses a substantially planar agitator comprising a plurality of heart-shaped wire lobes rotated on a vertical shaft within a cylindrical hopper having a perforate bottom. The lobes are biased into contact with the perforate bottom. A series of connecting shafts and universal joints, and a mechanical speed control connect the agitator to a motor horizontally mounted to the side of the hopper.
A version of the Case apparatus presently manufactured by Be-Mo Machine Co. avoids the universal joints by using a right angle gear drive. The agitator is driven by a right-angle bevel gearbox within the hopper, connected by a horizontal shaft passing through the wall of the hopper to a one-third horsepower motor equipped with a mechanical speed control. An electrically operated clutch, within the mechanical speed control, disconnects the agitator drive when conveyor operation is halted.
A disadvantage of these prior art devices is that stray powder accumulates in and clogs the motor, speed control, clutch and related agitator drive components, resulting in a significant loss of productivity due to down-time for daily cleaning of the drive.
Another disadvantage of these prior art devices is the low efficiency of the angled drive power train through the wall of the hopper to the agitator. This results in a requirement for a large, bulky motor that is expensive, hard to control, and wasteful of electrical power.
Another disadvantage of these prior art devices is the presence of wearing drive components within the hopper, and wear between the agitator and the perforate hopper bottom, resulting in contamination of the powder by metal particles and lubricant.
Another disadvantage of these prior art devices is that the wire lobes of the agitator, flexing in contact with the hopper bottom, often fracture after a period of use necessitating frequent disassembly and repair or replacement of the agitator.
A further disadvantage of these prior art devices is that the additional power required to operate the agitator in rubbing contact with the screen compounds the requirement for a large, bulky, expensive motor.
Thus, there is a need for apparatus to meter, sift, and feed powder that is inexpensive, does not permit stray powder to clog the components of the drive, does not contaminate the powder, and is not subject to frequent mechanical failure of the agitator.